Optoelectronic components or active optical devices, in conjunction with optical fibers, are used for optical data transmission and reception, data storage, printing, laser pumps and a multitude of other applications. Data transmission over optical fiber will eventually surpass data transmission over copper wire because of the superior transmission capabilities of optical fiber. Specifically, while copper is reliable, it cannot operate at high signal transfer rates. For data transfer rates exceeding 50 Mb/s, special systems copper wiring is required. For data transfer rates over 150 Mb/s, use of even the best copper wiring available is questionable.
Optical fiber, on the other hand, can handle data transmission rates hundreds of times that of copper. For example, current optical fiber systems can easily handle 40 Gb/s over a single fiber. And advances in technology will only result in increases in data transfer rates over a single fiber.
As a result, to meet the data transfer rate demand generated by the dramatic increase in Internet users, related bandwidth intensive applications, virtual private networking (VPN), storage area networking (SAN) and other rich media streaming over the Internet, telecommunications carriers have designed and installed new networks based upon optical fiber, have deployed additional fiber in their existing networks and have used advances in optical technologies such as dense wavelength-division multiplexing (DWDM).
In all communications networks relying upon the use of optical fiber, the fibers must be coupled to optoelectric components, such as light emitting devices and light receiving elements. Typically, the communication path is in the form of an optical fiber, the ends of which are coupled to light transmitting and light receiving elements. In order to assure maximum optical coupling between the ends of the fibers and the optical devices to which they are coupled, it is important to precisely fix the axial distance between the end of the fiber and the face of the optical element to which it is to be coupled as well as accurately aligning the end of the fiber with the prescribed location on the surface of the light emitting or light receiving element.
Further, with respect to the coupling of an optical fiber to a photodiode, currently available coupling devices are bulky, complex and incur a high cost of manufacture while failing to provide the compact size needed for current and future optical system components. For example, a typical photodiode optical fiber ferrule attachment requires an imaging lens, a mirror or both, all disposed between the fiber and the photodiode detector. Further, a two or three dimensional photodiode-fiber alignment process is required in order to optimize the coupling efficiency. Thus, this process is complicated and costly especially for single-mode fiber application where accurate alignment is required.
Therefore, there is a need for an improved method for coupling photodiodes to optical fibers which achieves the requisite coupling efficiency and which lowers the manufacturing costs by providing a less complicated process.